editor/libeditor/DeleteTextTransaction.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef DeleteTextTransaction_h
   7 #define DeleteTextTransaction_h
   8
   9 #include "EditTransactionBase.h"
  10
  11 #include "EditorForwards.h"
  12
  13 #include "mozilla/dom/Text.h"
  14 #include "nsCOMPtr.h"
  15 #include "nsCycleCollectionParticipant.h"
  16 #include "nsID.h"
  17 #include "nsString.h"
  18 #include "nscore.h"
  19
  20 namespace mozilla {
  21
  22 /**
  23  * A transaction that removes text from a content node.
  24  */
  25 class DeleteTextTransaction final : public EditTransactionBase {
  26  protected:
  27   DeleteTextTransaction(EditorBase& aEditorBase, dom::Text& aTextNode,
  28                         uint32_t aOffset, uint32_t aLengthToDelete);
  29
  30  public:
  31   /**
  32    * Creates a delete text transaction to remove given range.  This returns
  33    * nullptr if it cannot modify the text node.
  34    *
  35    * @param aEditorBase         The provider of basic editing operations.
  36    * @param aTextNode           The content node to remove text from.
  37    * @param aOffset             The location in aElement to begin the deletion.
  38    * @param aLenthToDelete      The length to delete.
  39    */
  40   static already_AddRefed<DeleteTextTransaction> MaybeCreate(
  41       EditorBase& aEditorBase, dom::Text& aTextNode, uint32_t aOffset,
  42       uint32_t aLengthToDelete);
  43
  44   /**
  45    * Creates a delete text transaction to remove a previous or next character.
  46    * Those methods MAY return nullptr.
  47    *
  48    * @param aEditorBase         The provider of basic editing operations.
  49    * @param aTextNode           The content node to remove text from.
  50    * @param aOffset             The location in aElement to begin the deletion.
  51    */
  52   static already_AddRefed<DeleteTextTransaction>
  53   MaybeCreateForPreviousCharacter(EditorBase& aEditorBase, dom::Text& aTextNode,
  54                                   uint32_t aOffset);
  55   static already_AddRefed<DeleteTextTransaction> MaybeCreateForNextCharacter(
  56       EditorBase& aEditorBase, dom::Text& aTextNode, uint32_t aOffset);
  57
  58   /**
  59    * CanDoIt() returns true if there are enough members and can modify the
  60    * text.  Otherwise, false.
  61    */
  62   bool CanDoIt() const;
  63
  64   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DeleteTextTransaction,
  65                                            EditTransactionBase)
  66   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
  67
  68   NS_DECL_EDITTRANSACTIONBASE
  69   NS_DECL_EDITTRANSACTIONBASE_GETASMETHODS_OVERRIDE(DeleteTextTransaction)
  70
  71   MOZ_CAN_RUN_SCRIPT NS_IMETHOD RedoTransaction() override;
  72
  73   dom::Text* GetText() const { return mTextNode; }
  74   uint32_t Offset() const { return mOffset; }
  75   uint32_t LengthToDelete() const { return mLengthToDelete; }
  76
  77   friend std::ostream& operator<<(std::ostream& aStream,
  78                                   const DeleteTextTransaction& aTransaction);
  79
  80  protected:
  81   // The provider of basic editing operations.
  82   RefPtr<EditorBase> mEditorBase;
  83
  84   // The CharacterData node to operate upon.
  85   RefPtr<dom::Text> mTextNode;
  86
  87   // The offset into mTextNode where the deletion is to take place.
  88   uint32_t mOffset;
  89
  90   // The length to delete.
  91   uint32_t mLengthToDelete;
  92
  93   // The text that was deleted.
  94   nsString mDeletedText;
  95 };
  96
  97 }  // namespace mozilla
  98
  99 #endif  // #ifndef DeleteTextTransaction_h